JPH04241709A - Inter-shaft phase change device - Google Patents

Abstract

PURPOSE:To prevent gear noise from generating from between gears which compose an accelerating gear mechanism at the time of changing non-phase, and prevent abrasion of the gears. CONSTITUTION:A phase change mechanism 10 for changing rotational phases of a cam shaft 1 and a housing 2 and a planetary gear mechanism 9 serving as an amplification gear mechanism for amplifying the rotational phases are installed between the cam shaft 1 and the housing 2. The planetary gear mechanism 9 consists of a ring gear 11 fixed on the housing 2, a sun gear 12 fixed on the cam shaft 1, a carrier 13, and a planetary gear 14. The phase change mechanism 10 is provided with a piston 8, and helical splines 8a, 8b provided on the inner/outer circumference thereof meshed with helical splines 3a, 15a of the housing 2 and the carrier 13. Hydraulic pressure and energization force by a return spring 24 are acted on a piston 8, and the piston 8 is moved in the longitudinal direction thereof by adjusting the magnitude of the hydraulic pressure.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to an inter-shaft phase shift device, which is used to control the opening and closing timing of intake and exhaust valves in an internal combustion engine according to the operating condition of the engine. The present invention relates to an inter-shaft phase changing device such as a valve timing control device that changes the rotational phase of the valve timing control device.

0002

[Prior art] Conventionally, for example, Utility Model Application No. 59-156102
The publication discloses a phase conversion device (camshaft drive device) using a planetary gear mechanism. In this technique, as shown in FIG. 9, a camshaft 61 is divided into an input shaft 61a drivingly connected to a crankshaft 62 and an output shaft 61b having a cam 63. A planetary gear mechanism 64 is provided between both shafts 61a and 61b.
is mediated. The planetary gear mechanism 64 includes a carrier 65 attached to the end of the input shaft 61a, and a plurality of planetary gears 6 rotatably supported by the carrier 65.
6, a ring gear 67 that meshes with the outer circumference of the planetary gear 66, and a sun gear 68 that is attached to the end of the output shaft 61b and meshes with the inner circumference of the planetary gear 66. The ring gear 67 is rotated by a piston 70 that protrudes and retracts from the cylinder 69.

According to this device, when the ring gear 67 is rotated by the protrusion and retraction of the piston 70, the carrier 65 and the sun gear 68 are rotated by different angles. This results in
The rotational phases of the crankshaft 62 and the output shaft 61b are shifted, and the opening/closing timing of the intake and exhaust valves can be changed while the engine is running.

0004

However, in the conventional phase changing device, the piston 70 does not operate and the ring gear 67 remains stationary during non-phase changing, so it is necessary to constantly rotate the planetary gear 66 and the sun gear 68. There is. Therefore, there have been problems such as gear noise occurring due to backlash between these gears 66, 67, and 68, and gear wear.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to rotate the ring gear, carrier, planetary gear, and sun gear integrally during non-phase conversion, and to eliminate gear noise, wear, etc. between the gears. An object of the present invention is to provide an inter-axis phase conversion device that can prevent the above problems.

[0006]

[Means for Solving the Problems] In order to achieve the above object, in the inter-axis phase conversion device of the present invention, a drive system having a drive shaft and a driven system having a driven shaft have a A phase conversion mechanism capable of changing the rotational phase of the driven shaft is provided, and the drive system and the driven system are provided with a combination of a plurality of gears, and when the phase conversion mechanism changes the phase, the rotation phase of the driven shaft relative to the drive shaft is changed. A speed increasing gear mechanism is provided which amplifies the rotational phase of the gears and rotates all of the gears together when the phase conversion mechanism is not performing phase conversion.

[0007]

[Operation] During non-phase conversion of the inter-axle phase conversion device, all gears constituting the speed increasing gear mechanism rotate integrally. Therefore, gear noise and wear between the gears in the speed increasing gear mechanism are prevented. Furthermore, during phase conversion, the rotational phase of the driven shaft relative to the drive shaft, which has been changed by the phase conversion mechanism, is amplified by the speed increasing gear mechanism.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the inter-shaft phase shift device of the present invention is embodied in a valve timing control device for an internal combustion engine will be described below with reference to FIGS. 1 to 4. FIG. 1 is a partially enlarged sectional view of a valve timing control device. The purpose of this valve timing control device is to control the opening and closing timing of the intake valve according to the operating state of the engine as an internal combustion engine, and for this purpose, the rotational phase of the crankshaft (not shown) and the intake camshaft 1 is adjusted. I'm trying to convert it.

Front end of camshaft 1 (left end in FIG. 1)
A housing 2 is attached to the housing 2. housing 2
consists of a cylinder 5 made up of two members with different diameters (a small diameter part 3 and a large diameter part 4) arranged concentrically, and a timing pulley 6 formed on the outer periphery of the front end of the large diameter part 4. The small diameter portion 3 is rotatably fitted onto the camshaft 1 . Further, the timing pulley 6 and the crankshaft are drivingly connected by a timing belt 7, and the rotation of the crankshaft is transmitted to the housing 2 via the timing belt 7. In addition,
In this embodiment, the crankshaft (drive shaft), timing belt 7, and housing 2 constitute a drive system, and the camshaft (driven shaft) 1 constitutes a driven system.

A phase conversion mechanism 10 for changing the rotational phase of the camshaft 1 and the housing 2, and a planetary gear mechanism 9 as an amplification gear mechanism for amplifying the angle of the same rotational phase are incorporated between the camshaft 1 and the housing 2. There is. The planetary gear mechanism 9 includes a plurality of gears such as a ring gear 11, a sun gear 12, a carrier 13, and a planetary gear 14. A ring gear 11 is fixed to the inner periphery of the front end of the timing pulley 6,
The sun gear 12 is fixed to the front end of the camshaft 1 with a bolt 20. The carrier 13 has a substantially circular shape,
It is rotatably fitted onto the camshaft 1 immediately behind the sun gear 12 between thrust washers 13' and 13''. A cylindrical portion 15 protrudes rearward from the carrier 13.
The outer peripheral surface of the cylindrical portion 15 is inscribed in a bearing 16 on the inner periphery of the front end of the large diameter portion 4. Therefore, the carrier 13 includes the camshaft 1, thrust washers 13', 13'' and the bearing 1.
It rotates while sliding in contact with 6.

A plurality of (for example, three) support shafts 17 are provided protruding from the outer periphery of the front surface of the carrier 13, and a planetary gear 14 is rotatably supported on each support shaft 17. Each planetary gear 14 includes the ring gear 11 and the sun gear 12.
The rotation of the timing pulley 6 is transmitted to the camshaft 1. A blocking ring 1 is attached to the front end of each support shaft 17.
8 is fixed, and the planetary gear 1 is connected from the same support shaft 17.
4 is prevented from falling off.

Next, the phase conversion mechanism 10 will be explained. The small diameter portion 3 and the large diameter portion 4 of the housing 2 and the carrier 1
A substantially cylindrical piston 8 with both front and rear sides open is disposed in the space surrounded by the piston 3 and the piston 8 . Helical splines 8a and 8b are formed on the inner circumferential surface of the front end and the outer circumferential surface of the front end of the piston 8. Both helical splines 8
a and 8b mesh with a helical spline 3a formed on the outer periphery of the small diameter portion 3 and a helical spline 15a formed on the inner circumferential surface of the cylindrical portion 15 of the carrier 13, respectively. Therefore, when a force is applied to the piston 8 in the longitudinal direction, the piston 8 moves in the longitudinal direction while rotating.

A pressurizing chamber 19 is formed between the piston 8 and the deepest part of the housing 2, and hydraulic oil is supplied to the pressurizing chamber 19. That is, an oil passage 21 is formed in the camshaft 1 and the housing 2, and this oil passage 21 communicates with the pressurizing chamber 19. and,
Hydraulic oil sucked up by an oil pump (not shown) and regulated by a hydraulic control valve 22 is transferred to the oil passage 2.
1 and is supplied to the pressurizing chamber 19. A forward pressing force acts on the piston 8 due to the hydraulic pressure of the supplied hydraulic oil. A locking ring 23 is fixed to the inner circumferential surface of the front end of the large diameter portion 4 of the housing 2, and a return spring 24 made of a coil spring is in a compressed state between the locking ring 23 and the outer circumference of the rear end of the piston 8. It is mediated by The return spring 24 always urges the piston 8 backward.

Therefore, when hydraulic oil is not supplied to the pressurizing chamber 19 (during advance), the biasing force of the return spring 24 positions the piston 8 at the rear end as shown in FIG. When hydraulic oil is supplied to the pressurizing chamber 19 from this state, the piston 8 moves forward while rotating against the biasing force of the return spring 24. At this time, the rotational phase of the housing 2 and the carrier 13, which are drivingly connected to the piston 8 by the helical splines 3a, 8a, 8b, and 15a, shifts, and accordingly, the rotational phase of the camshaft 1 and the crankshaft is retarded. It will shift.

Incidentally, the opening degree of the hydraulic control valve 22 is controlled by an electronic control unit (hereinafter simply referred to as "ECU") 25. That is, on the input side of the ECU 25, there are a throttle sensor 26 that detects the opening degree of the throttle valve as the engine load, and a rotation speed sensor 27 that detects the engine rotation speed from the rotation of the distributor rotor.
are connected. Further, a hydraulic control valve 22 is connected to the output side of the ECU 25. In ECU25,
Figure 4 shows the relationship between engine speed and engine load.
First to third areas A, B, and C as shown in are stored in advance. The ECU 25 determines the current engine state from the first to third regions A to C based on the detection signals from the throttle sensor 26 and the rotation speed sensor 27, and controls the opening degree of the hydraulic control valve 22. Outputs control signals for

Next, the operation and effects of the valve timing control device of this embodiment constructed as described above will be explained. When the engine is started, the rotation of the crankshaft is transmitted to the housing 2 via the timing belt 7. Further, the ECU 25 inputs signals from the throttle sensor 26 and the rotational speed sensor 27 to detect the engine load and the engine rotational speed, and the engine state at that time is determined by the above-mentioned 3.
Determine which area it belongs to among the three areas A to C. Then, the ECU 25 outputs a control signal to the hydraulic control valve 22 to set the rotational phase of the camshaft 1 relative to the crankshaft to a rotational phase corresponding to the determined regions A to C.

FIG. 1 shows the valve timing control system when the ECU 25 determines that the engine condition is in the first region A (low/medium rotation and high load region). In this state, the hydraulic control valve 22 is closed, and the pressurizing chamber 19
Hydraulic oil is not supplied to. Therefore, the piston 8 urged rearward by the return spring 24 is located at the rear end inside the housing 2.

If the piston 8 remains located at the rear end of the housing 2 and does not move forward or backward, the camshaft 1, the planetary gear mechanism 9, the piston 8, and the housing 2
rotates as one. This means that the piston 8 is spline-coupled to the small diameter portion 3 of the housing 2, and the piston 8 is
This is because the carrier 13 is spline-coupled to the carrier 13, and the planetary gear 14 supported by the carrier 13 meshes with the ring gear 11 and the sun gear 12. The rotational torque transmitted to the housing 2 via the timing belt 7 is transmitted to the camshaft 1 through the following two routes. One of them is a path that is transmitted to the camshaft 1 via the helical splines 8a, 8b of the piston 8 and the planetary gear mechanism 9, and the remaining one is a path that is transmitted directly from the ring gear 11 fixed to the timing pulley 6 to the planetary gear mechanism. This is a path that is transmitted to the camshaft 1 via 9.

As mentioned above, the piston 8 is attached to the housing 2
If it is located at the rear end, the closing timing of the intake valve will be advanced, making it difficult for the air-fuel mixture sucked into the cylinder to return. As a result, intake air filling efficiency is increased and high output is obtained. Further, FIG. 2 shows the valve timing control device when the ECU 25 determines that the engine state has shifted from the first region A to the second region B (low rotation and low load region). In this state, the ECU 25 outputs a control signal to open the hydraulic control valve 22. When the hydraulic control valve 22 opens to a predetermined opening degree, the hydraulic oil sucked up by the oil pump is pressure regulated by the hydraulic control valve 22, and passes through the oil passage 21 as shown by the arrow into the pressurizing chamber 1.
9. The hydraulic pressure of the supplied hydraulic oil acts on the rear surface of the piston 8 and pushes the piston 8 forward against the biasing force of the return spring 24. Then, the piston 8 rotates and moves forward due to the action of the helical splines 3a, 8a, 8b, and 15a, and a torsional force is applied to the housing 2 and the carrier 13 accordingly. This torsional force causes the housing 2 and the carrier 13 to rotate relative to each other. Note that the forward movement of the piston 8 is restricted when it comes into contact with the rear surface of the carrier 13.

The amount of rotational phase conversion at this time is expanded by the planetary gear mechanism 9. That is, the rotational phase of sun gear 12 with respect to ring gear 11 can be considered based on the following equation. (1+λ)Cn =Rn +λ・Sn (1)
Here, λ is the diameter ratio of the sun gear 12 to the ring gear 11, Cn is the rotation speed of the carrier 13, Rn is the rotation speed of the ring gear 11, and Sn is the rotation speed of the sun gear 12.

To simplify the explanation, the ring gear 11 is fixed as shown in FIGS. 2 and 3, and the rotational force of the crankshaft is input to the carrier (not shown in FIG. 3) 13 and is transmitted from the sun gear 12. It shall be output. This is because the phase difference occurring between the ring gear 11 and the carrier 13 is considered by replacing it with the rotation of the carrier 13 by fixing the ring gear 11.

Since the ring gear 11 is fixed as described above, Rn=0. Substituting this into equation (1) gives the following equation (2). {(1+λ)/λ}Cn = Sn (2) Therefore, the sun gear 12 rotates by (1+λ)/λ times that of the carrier 13, and the rotational phase caused by the rotation of the piston 8 is added to the planetary gear mechanism 9. By doing {(1+λ
)/λ} times.

Let's now consider specific values in equation (2). Assume that a phase difference (phase angle) of 10° occurs between the housing 2 and the carrier 13 due to the rotation of the piston 8. Further, the diameter ratio λ of the sun gear 12 to the ring gear 11 is set to 0.5. Substituting these values into equation (2), Sn = {(1+0.5)/0.5}・10=3×
10=30. In other words, the sun gear 12 is 3 times the phase difference (10°) between the housing 2 and the carrier 13.
A phase difference of 0° will be obtained. Note that the diameter ratio λ preferably ranges from 0.3 to 0.6, and the preferable magnification of the phase angle transmitted to the sun gear 12 with respect to the phase angle input to the carrier 13 is about 2.6 to 4.4. It is.

Therefore, due to the expansion of the phase angle, the closing timing of the intake valve is extremely delayed in a region where both the engine load and the engine speed are low. Thereby, the cylinder volume can be reduced in appearance and pumping loss can be reduced. Pumping loss here refers to intake loss that occurs when the engine takes in the air necessary to perform work to the outside.

Although not shown in the drawings, when the engine state shifts from the first region A or the second region B to the third region C, the ECU 25 operates to slightly open the hydraulic control valve 22. Outputs a control signal. At this time, piston 8
The piston 8 moves to a position where the magnitude of the hydraulic pressure applied to the rear end surface and the biasing force generated by compression of the return spring 24 are balanced. At this time, the amount of movement of the piston 8 and the amount of relative rotation of the camshaft 1 are smaller than when moving from the first region A to the second region B. Therefore, the closing timing of the intake valve is later than in the first region A and earlier than in the second region B, and the amount of valve overlap is reduced. As a result, more air-fuel mixture can be taken into the cylinder due to intake inertia. Note that the magnitude of the hydraulic pressure applied to the piston 8 at this time can be adjusted by changing the opening degree of the hydraulic control valve 22.

As described above, in this embodiment, the piston 8 and the planetary gear mechanism 9 are interposed between the housing 2 having the timing pulley 6 and the camshaft 1. and,
The piston 8 and the housing 2 are connected by a helical spline 8a.
, 3a, and the piston 8 and carrier 13 were also connected by helical splines 8b, 15a. Furthermore, the ring gear 11 was fixed to the housing 2, and the sun gear 12 was fixed to the camshaft 1, respectively. As a result, during normal times (during non-phase change) when the engine condition belongs to any one of the first to third regions A to C, all components of the valve timing control device rotate integrally. However, no relative rotation occurs. Therefore, ring gear 6
7 is fixed, and a planetary gear 66 and a sun gear 6
Unlike the prior art in which gear 8 rotates all the time, this embodiment can prevent gear noise from occurring due to backlash between gears and gear wear during non-phase conversion.

Further, when the operating state of the engine shifts from one of the first to third regions A to C to another region, the phase change mechanism 10 changes the relationship between the camshaft 1 and the carrier 13. The rotational phase can be changed and the phase angle can be further amplified by the planetary gear mechanism 9. Therefore, a large displacement angle of the camshaft 1 can be obtained. The magnitude of this displacement angle is determined by the helical splines 3a, 8a, 8b,
Various settings can be made by appropriately changing the helix angle of 15a and the diameter ratio of sun gear 12 and ring gear 11.

Furthermore, according to this embodiment, the following functions and effects are achieved in addition to the above-mentioned ones. For example, if the planetary gear mechanism 9 is omitted and only a mechanism that changes the rotational phase of the housing and the camshaft by moving a piston having a helical spline in the axial direction is used, the phase angle will change in the axial direction of the piston. is determined by the amount of movement. Therefore, the only way to increase the phase angle is to increase the amount of movement of the piston or increase the torsion angle of the helical spline, and the degree of freedom in design is small. On the other hand,
In this embodiment, since the planetary gear mechanism 9 is added as described above, not only can the phase angle be easily expanded using the planetary gear mechanism 9, but also the diameter of the sun gear 12 and ring gear 11 can be increased. By appropriately selecting the ratio, the expansion rate of the phase angle can be selected, and the degree of freedom in design increases accordingly. (Second Embodiment) Next, a second embodiment of the present invention will be described in FIGS. 5 to 7.
Explain according to the following.

This embodiment differs greatly from the first embodiment in that a step motor 35 is used instead of the hydraulic pressure and the return spring 24 as means for moving the piston 8 in the longitudinal direction. That is, FIG. 5 shows the state of the valve timing control device when the valve timing is advanced, and FIG. 6 similarly shows the state when the valve timing control device is retarded. As shown in both figures, a housing 2 whose rear surface is open is rotatably supported at the front end of the camshaft 1 (left end in the figures). A phase conversion mechanism 10 for changing the rotational phase of the camshaft 1 and the housing 2, and a planetary gear mechanism 9 for amplifying the rotational phase angle are disposed between the camshaft 1 and the housing 2. As shown in FIG. 7, the piston 8 of the phase angle conversion mechanism 10 includes a ring-shaped main body part 30 having helical splines 8a and 8b on the inner and outer peripheries, and a plurality of splines protruding forward at equal angles from the front end of the main body part 30. (for example, three) connecting pieces 31. These connecting pieces 31 pass through holes 2b provided in the deepest part of the housing 2. A connecting ring 32 is fixed to the inner peripheral surface of the front end of the connecting piece 31.

On the other hand, as shown in FIG. 5, a stationary member such as the timing belt cover 33 located in front of the camshaft 1 has a cylindrical portion 34 projecting rearward. A step motor 35 is attached to the front surface of the timing belt cover 33, and its rotating shaft 36 is connected to the cylindrical portion 3.
4 and is supported by the front end of the camshaft 1 so as to be relatively rotatable. The step motor 35 is controlled by the ECU.
The angle rotation shaft 36 is rotated in accordance with the number of pulse signals output from 25. A feed screw 37 is formed on the outer periphery of the rotating shaft 36, and a nut 38 is screwed onto the feed screw 37. The outer periphery of the nut 38 and the inner periphery of the cylindrical portion 34 are spline-coupled, so that when the rotating shaft 36 of the step motor 35 rotates, the nut 38 moves in the front-rear direction.

Furthermore, a thrust bush 39 is attached to the outer periphery of the rear end of the nut 38.
A connecting ring 32 at the front end of the piston 8 is connected to the piston 8 for relative rotation. Here, the thrust bush 39 is used because the nut 38 does not rotate relative to the connecting ring 3.
Reference numeral 2 denotes a rotating member that rotates as the engine rotates, and is used to cut off rotation and reduce frictional resistance due to relative rotation between the nut 38 and the connecting ring 32. In addition,
A thrust bearing may be used instead of the thrust bush 39. The configuration other than the above is the same as that of the first embodiment.

Therefore, according to this embodiment, during the non-phase conversion shown in FIG. The components of the valve timing control device, such as the following, rotate integrally. Therefore, generation of gear noise due to backlash between gears and gear wear can be prevented.

Furthermore, during phase conversion, the rotating shaft 36 of the step motor 35 rotates based on a control signal from the ECU 25, and the nut 38 on the rotating shaft 36 moves forward or backward. Since the piston 8 is connected to the nut 38 via the thrust bush 39, the piston 8 moves while rotating relative to the housing 2. This results in
The rotational phase of the piston 8 relative to the housing 2 is changed, and the phase angle is expanded by the planetary gear mechanism 9.

Furthermore, in this embodiment, the step motor 35
By using this, the following effects can also be achieved. In the case where hydraulic pressure and the return spring 24 are used as a method for moving the piston 8, when trying to obtain stepless or multistage phase change, the hydraulic pressure applied to the piston 8 and the biasing force of the return spring 24 are balanced. It is necessary to keep the piston 8 stationary in position. At this time, the accuracy of the resting position of the piston 8 may be affected by the hydraulic pressure and the accuracy of the return spring 24. Therefore, in order to apply the hydraulic pressure according to the set value to the piston 8, taking into consideration the oil temperature, hysteresis of the hydraulic pressure control valve 22, etc., for example, a separate sensor to detect the position of the piston 8 is installed, and the piston It is conceivable to control the oil pressure or the like so that the position 8 becomes a predetermined position.

Further, when the piston 8 is moved to the set position, the piston 8 is in an unstable state balanced by the oil pressure and the return spring 24. If the position of the piston 8 is unstable, there is a risk that the piston 8 will deviate from the set position due to external input such as torque fluctuation due to rotation of the camshaft 1. Therefore, it is desirable to provide another mechanism to maintain the position of the piston 8.

On the other hand, in this embodiment, the longitudinal position of the piston 8 is determined by the rotation angle of the rotating shaft 36 of the step motor 35. Therefore, the position of the piston 8 can be controlled with high accuracy without using a special sensor as described above. Further, since the step motor 35 has a self-holding torque, the piston 8 can be stably held at a predetermined position without providing a special holding mechanism as described above.

Furthermore, in this embodiment, since hydraulic pressure is not used to move the piston 8, there is no need to form an oil passage in the camshaft 1 or the housing 2. (Third Embodiment) Next, a third embodiment of the present invention will be described based on FIG. 8. This embodiment differs greatly from the first and second embodiments in that a differential gear mechanism 41 is used instead of the planetary gear mechanism 9 as the speed-increasing gear mechanism. In addition, in Figure 8, the timing belt 7 is on the rear side (on the right side of the figure).
It is located in

The camshaft 1 is divided into an input shaft 42 and an output shaft 43, both of which are connected to the operating gear mechanism 4.
connected by 1. The operating gear mechanism 41 covers the ends of both shafts 42 and 43, and has a cylindrical portion 44 at the rear end.
a case 44, input side and output side bevel gears 45, 46 fixed to the ends of the shafts 42, 43 in the case 44, rotatably supported by the case 44, and both the bevel gears It consists of gears 45, 46 and other bevel gears 47, 48 that mesh with them. The bevel gear 46 on the output side is formed to have a smaller diameter than the bevel gear 45 on the input side.

On the other hand, on the input shaft 42, the housing 2 is rotatably supported between the timing pulley 6 and the operating gear mechanism 41. housing 2
A cylindrical piston 8 is disposed inside. piston 8
is spline-coupled to the cylindrical portion 44a and the input shaft 42 by helical splines 49, 50. An oil passage 21 is formed in the input shaft 42, and hydraulic oil is supplied into the housing 2 through the oil passage 21 when the angle is retarded, but no hydraulic oil is supplied when the angle is advanced.

In the valve timing control device configured as described above, the piston 8 does not move in the longitudinal direction during non-phase conversion, and the input shaft 42, the piston 8, and the case 4
4. All the bevel gears 45 to 48 and the output shaft 43 rotate together. Therefore, the rotational phases of the input shaft 42 and the output shaft 43 do not change. Also, housing 2
When the supply of hydraulic oil into the input shaft 42 is started or stopped, the piston 8 moves in the front-rear direction while rotating relative to the input shaft 42. Since a case 44 is connected to the piston 8 by a helical spline 49, the case 44
rotates together with the piston 8. As a result, the bevel gear 47
, 48 revolve on the input side bevel gear 45 while rotating, and the output side bevel gear 46 is sped up and rotated by the same revolution. Therefore, the rotational phase is expanded by the operating gear mechanism 41, and a large shift angle of the output shaft 43 is obtained.

[0041] In this way, according to this embodiment as well, the first
And the same operation and effect as the second embodiment is achieved. It should be noted that the present invention is not limited to the configuration of the embodiments described above, and may be modified as desired without departing from the spirit of the invention, for example, as described below. (1) A sprocket may be used in place of the timing pulley 6 in each of the above embodiments, and the crankshaft and the sprocket may be drivingly connected by a chain. (2) The valve timing control device of each of the embodiments described above can be applied to a type of engine in which the intake camshaft 1 and the exhaust camshaft are drivingly connected by a scissor gear. In this case, a valve timing control device is provided between the scissor gear and the camshaft. (3) Helical splines 8a on the inner and outer peripheries of the piston 8,
Either one of 8b may be changed to a spline. (4) A valve timing control device similar to that of each of the above embodiments may be attached to the exhaust camshaft. (5) The present invention is applicable not only to valve timing control devices for internal combustion engines but also to devices that require phase conversion between two axes.

[0042]

As described in detail above, according to the present invention, a phase conversion mechanism is provided between a driving system and a driven system, and a combination of a plurality of gears is provided, and the rotational phase is changed during phase conversion by the phase conversion mechanism. In addition, a speed increasing gear mechanism is provided that rotates all of the gears together during non-phase conversion, so gear noise may be generated between the gears or the gears may wear out during non-phase conversion. It is possible to reliably prevent this, and furthermore, it has the excellent effect of being able to obtain a large displacement angle during phase conversion.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a valve timing control device in a first embodiment when no oil pressure is applied to a piston.

FIG. 2 is a sectional view of the valve timing control device when hydraulic pressure is applied to the piston in the first embodiment.

FIG. 3 is a diagram showing the positional relationship of each gear of the planetary gear mechanism in the first embodiment.

FIG. 4 is a diagram showing the relationship between engine speed and engine load in the first embodiment.

FIG. 5 is a sectional view of the valve timing control device when the piston is moved rearward by the step motor in the second embodiment.

FIG. 6 is a sectional view of the valve timing control device when the piston is moved forward by the step motor in the second embodiment.

FIG. 7 is a perspective view of a piston in a second embodiment.

FIG. 8 is a sectional view showing a schematic configuration of a third embodiment.

FIG. 9 is a perspective view showing a conventional phase conversion device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Camshaft as a driven system, 2... Housing forming part of the drive system, 7... Timing belt forming part of the drive system, 9... Planetary gear mechanism as a speed increasing gear mechanism, 10... Phase Conversion mechanism, 41...operating gear mechanism as a speed increasing gear mechanism

Claims (1)

[Claims] 1. A phase conversion mechanism capable of changing the rotational phase of the driven shaft with respect to the driving shaft is provided between a driving system having a driving shaft and a driven system having a driven shaft, and the driving system and the driven shaft are The drive system includes a combination of a plurality of gears, and amplifies the rotational phase of the driven shaft relative to the drive shaft during phase conversion by the phase conversion mechanism, and amplifies the rotational phase of the driven shaft with respect to the drive shaft during phase conversion by the phase conversion mechanism, and amplifies all of the gears during non-phase conversion by the phase conversion mechanism. An inter-axle phase conversion device characterized by being provided with a speed-increasing gear mechanism that integrally rotates.